September 29 – October 1, 2008Doubletree Hotel Seattle Airport – Seattle, Washington

InvaLite Hybrid Tooling System for Advanced Composite Structure

Tom Sobcinski

Tooling Segment Manager

Remmele Engineering, Inc.

Overview

• Looking back at tooling for composites

• Finding an alternative to all-Invar, all-composite tooling

• InvaLite hybrid tool concept

• Design & testing

• Looking forward

Looking Back at Tooling forComposites

• In the 1980s, tools made from composites were the industry standard for aerospace manufacturing

– Light weight

– Close CTE match to the part

– Cost of masters could be amortized across rate tools

Looking Back at Tooling forComposites

• As rates increased composite tooling suffered substantial negatives

– Durability issues

– Replacement tools and repairs impacted cost of ownership

– Potential for tool failure during cure placed high value parts in jeopardy

– Limited supply chain for all-composite tooling

Looking Back at Tooling forComposites

• In the late 1980s, the aerospace industry started a shift to metals-based production tooling

– Invar becomes the baseline for tools used in production of advanced composite parts

– CTE closely matches CF/EP parts

– Durability reduces cost of ownership

– Tools last for life of program

Today

• As Aerospace OEMs and Tier 1’s start to produce larger integrated structure, they began to feel the limitations of Invar tooling

– Weight exceeds equipment capacities

– Reduced throughput due to longer cure cycles and decreased lay down rate on Automated Fiber Placement (AFP) equipment

Finding an Alternative

Goals

• Reduce tool weight

• Maintain durability & stability of Invar

• Cost competitive with other light weight solutions

• Ensure adequate supply chain for manufacture

Hybrid Tool Concept

• In 2007, Remmele developed a Hybrid Invar/composite tool concept

– Reduced thickness Invar face sheet

– Interlocking CF/BMI composite sub-structure

– Surface and support structure attached through bonded/fastened tongue & groove joints

Hybrid Tool Concept

• Weight reduction– Reduced thickness face sheet and CF/BMI sub-structure

translates into ~50% weight reduction over traditional Invar tooling

Hybrid Tool Concept

• Durability– The use of a metallic face sheet

provides the durability and vacuum integrity of Invar for the critical lay-up surface

– Minor alterations or continuous use will not induce leak paths

– Recurring cost benefit of Invar

Hybrid Tool Concept

• Stability– Analysis indicates Hybrid

Tooling provides reduced deflection over conventional Invar tooling

– Hybrid Tooling provides the CTE match needed for advanced composite curing

– Isotropic face sheet material provides predictable face sheet geometry at cure temperature with uniform CTE in all directions

Hybrid Tool Concept

• Cost and scheduling benefits– Hybrid tooling is cost-competitive with

CF/BMI composite tooling

– Additional cost for Invar masters eliminated

– Cost of ownership is lower

– Invar face sheet longevity means reduced repairs/replacement during life of tool

Hybrid Tool Concept

• Cost and scheduling benefits (cont’d.)– Reduced weight/mass over

conventional Invar = improved lay-down rates and reduced cure cycles

– Increases effective autoclave and AFP equipment capacity

– Reduces rate tool requirements

– Traditional metallic tooling supply chain

Cost Comparison

Invar Master Amortized Across (3) Tools

Totals

Invar Hybrid Carbon/BMI

Cost Comparison

4’ X 8’ Plate/Board

Hybrid Tool Concept

• Supply chain capability/capacity for tool manufacture

– Does not require expertise or capital equipment associated with composite manufacturing

– Composite sub-structure produced by water jet cutting of commercially available pre-molded CF/BMI boards

– Composite machining limited to interface joint

– Traditional tool manufacturers become part of the supply chain

– Use of both Invar and CF/BMI reduces pressure on material supply chain

Design and Testing

• July 2007: Remmele completes initial design specifications for a Hybrid Tool, conducts FEA analysis

• Fabricate and test sub-scale demonstrator tool for feasibility

• Refine design

Design and Testing

FEA analysis• Analysis indicates Hybrid Tooling provides ~50% weight

reduction with reduced deflection over conventional Invar tooling

Conventional Invar tool 31 lbs.- tool supported @ extremes with gravity load.

Invar/BMI Hybrid tool 13.4 lbs.- tool supported @ extremes with gravity load.

Building & Testing the Demonstrator

Fabricate and test small demonstrator• Sample parts were built from the demonstrator at Northwest

Airline’s composite repair facility in Eagan, Minnesota

Building & Testing the Demonstrator

Refine Design

• Continue development of Invar/Composite joint design

• Refine method of joining interlocked composite boards

• Develop reliable damage tolerant handling features

• Continue efforts towards refining design for manufacturability

Design and Testing

Researching composite materials

• CF/BMI materials found with CTE match to Invar 36, 5000 F. Tg and other required mechanical properties

• Source found to produce pre-molded quasi-isotropic CF/BMI boards and provide water jet cut sub-structure directly from CAD model

0

Joint Design: Invar / Composite

• Tongue and groove bonded/fastened construction

Design and Testing

Tensile testing

– Several bonded joint designs were tested

– Results shown for bonded only joints

– Average joint failure ~6,200 lbs. per linear inch

Looking Forward

• The concept is moving forward with a full-scale development tool with a major aerospace OEM partner

– Fourth quarter 2008 tool delivery

– Replaces existing production tool

– Jointly developing criteria for performance measurement/monitoring

– Results to be presented at future date

• Remmele Engineering continues to look at existing and new applications for the Hybrid design.

Looking Forward

Looking Forward

Finished Tool Weight- 162 Lbs.

Conclusion

InvaLite tooling offers advantages

• ~50% weight reduction over conventional Invar

• Cost competitive with CF/BMI

• Durability of Invar at critical tool layup surface

• Predictable face sheet geometry at elevated temperature

• Utilizes existing metallic tooling supply chain

• Use of both Invar and CF/BMI reduces pressure on material supply chain

Questions?

Thank you!

Tom Sobcinski, Tooling Segment Mgr. Remmele Engineering, Inc.

Phone: 651.635.4197

Email: tom.sobcinski@remmele.com